Studies will be continued on the mechanisms whereby chromosome imbalance results in abnormalities of development and function. The research goals for the coming year are: a) The isolation and analysis of trisomic and normal cell populations from normal reversibly yields trisomy 17 mouse chimeras for H-2 antigen synthesis and integration into membranes. b) The formation and analysis of normal reversibly yields monosomy 19 (1,12) chimeras to determine whether monosomy results in cell lethality. c) The analysis of protein synthesis in monosomic mouse embryos by 2-dimensional gel electrophoresis and ultrastructural examination of monosomy 19 embryos. d) The quantitation of interferon induced products in normal and trisomy 21 cells.